Synthesis and biological evaluation of (acyl)hydrazones and thiosemicarbazones obtained via in situ condensation of iminium salts with nitrogen-containing nucleophiles

Exploring the Structural Versatility and Dynamic Behavior of Acyl/Aroyl Hydrazones: A Comprehensive Review

Acyl and aroyl hydrazones are hydrazine derivatives with unique structural variations and multiple applications in various disciplines, including medicinal chemistry, materials, and agrochemicals research. The presence of numerous reactive sites in acyl hydrazones established it as a privileged structure class in organic chemistry and, hence, serve as an important intermediate in the synthesis of pharmaceutically significant compounds. The intrinsic nature of the acylhydrazone group leads to various dynamic processes, including conformational, configurational, and tautomeric interconversions. Their dynamic behavior in organic frameworks is mainly attributed to hindered rotation around the imine C=N bond and -CONH- amide bond. It is crucial to comprehend the geometrical and conformational behavior of hydrazone derivatives in order to understand their structural attributes, reactivity, and interactions with other molecules. This review article provides an in-depth and up-to-date examination of the geometrical and conformational properties of acyl and aroyl hydrazones showcasing chronological progression of advancements in N-acyl/aroyl hydrazones (NAHs) over time spanning from 1955 to 2025. The insights gained from this analysis will be a helpful resource for researchers and chemists working on designing and developing new compounds with improved characteristics for various applications in chemistry and medicine.

Mono- and di-acylated imidazolidine-2-thione derivatives: synthesis, cytotoxicity evaluation and computational studies

Imidazolidine-2-thione substructure represents a pharmaceutically attractive scaffold, being included in different antimicrobial, anticancer and pesticide agents. To further evaluate the pharmaceutical potential of this chemical moiety, imidazolidine-2-thione was reacted with atypical Vilsmeier adducts, obtained by the condensation between dimethylacetamide and various acyl chlorides endowed with different electronic and steric properties. The formation of mono-acylated or di-acylated thiourea derivatives emerged to be affected by the nature of the considered acyl chloride reagent. Computational semi-empirical simulations were carried out to rationalize the relevant factor influencing the outcome of the reaction. As acylthioureas are pharmacologically relevant compounds, the chemical versatility of mono-acylated derivatives were evaluated by reacting benzoyl imidazolidin-2-thione with acyl chlorides. A small library of asymmetric di-acylthioureas was prepared and the obtained derivatives did not show any cytotoxicity on SKOV-3 and MCF-7 cancer cell lines. Additionally, in silico studies predicted good pharmacokinetics properties and promising drug-like characteristics for mono- and di-acylated thioureas. These considerations further support the value of the prepared compounds as interesting non-cytotoxic chemical scaffold useful in the medicinal chemistry field.

An environment-friendly methodology for the construction of diversified bicycloacenaphtho[1,2-d]imidazole-8-thione scaffolds using spinel NiFe2O4 nanoparticles as a sustainable catalyst

Herein, we successfully developed an easy access to bicycloacenaphtho[1,2-d]imidazole-8-thione by one-pot three-component MCRs of acenaphthoquinone, aryl or alkyl isothiocyanates and amines using environmentally benevolent and recyclable spinel NiFe₂O₄ nanocatalyst in aqueous ethanol. A broad number of products have been synthesized with both EDGs and EWGs present in the ring which increases the diversity of the protocol. The NiFe₂O₄ nanopowder has been synthesized and thoroughly characterized by powdered XRD, HRTEM, EDX, BET and ICP-AES analysis. The protocol to this bicyclic-heterocycle is noteworthy due to good to excellent yields, practical simplicity and high regioselectivity without any troublesome or hazardous by-products and its easy recovery and reusability of the catalyst. Spinel NiFe₂O₄ NPs-catalysed synthesis of various bicycloacenaphtho[1,2-d]imidazole-8-thione scaffolds under mild and sustainable conditions.